Studies on Selected Microbial Biotransformations of Arsenic Compounds
type: CreativeWork
description: Arsenic is an element with a notorious history and reputation used both as a poison and a cure in its past. It has a complex biogeochemical cycle in nature which was investigated. The major portion of this project looked primarily at arsenobetaine. Arsenobetaine is a benign form of arsenic that is ubiquitous throughout the marine environment representing the major form of arsenical found in higher marine organisms. It is from this that a great deal of interest stems, as the human population has tried to reassure itself on the safety of seafood. The biodegradation of arsenobetaine is described, in specific its breakdown by mixed biota with analysis by HPLC-hydride generation-atomic fluorescence spectroscopy (HG-AFS). Subsequent selection within this consortium led us to four bacterial isolates that demonstrated the biodegradation of arsenobetaine to dimethylarsinate. Two of these isolates are identified to species level {Paenibacillus glucanolyticus and Pseudomonas fluorescens A). With analysis by HPLC-inductively coupled plasma-mass spectrometry (ICP-MS), the degradation of arsenobetaine is described by initial cleavage of the methyl arsenic bond to form dimethylarsinoylacetate, with subsequent cleavage of the carboxymethyl-arsenic bond to yield dimethylarsinate. It has been suggested that mixed community function would provide a means for the biodegradation of arsenobetaine, with different communities being capable of breaking the two different types of carbon-arsenic bonds. The present work indicates this is not an obligate requirement and evidence of the monoseptic culture degradation of arsenobetaine has been described. The biogenesis of arsenobetaine, a previously undescribed process, was also investigated. A lysed cell extract of Pseudomonas fluorescens A NCIMB 13944 was shown to transform dimethylarsinoylacetate to arsenobetaine and dimethylarsinate. Dimethylarsinoylacetate is seen as a likely intermediate in the biosynthesis pathway starting at dimethylarsin…
abstract: Arsenic is an element with a notorious history and reputation used both as a poison and a cure in its past. It has a complex biogeochemical cycle in nature which was investigated. The major portion of this project looked primarily at arsenobetaine. Arsenobetaine is a benign form of arsenic that is ubiquitous throughout the marine environment representing the major form of arsenical found in higher marine organisms. It is from this that a great deal of interest stems, as the human population has tried to reassure itself on the safety of seafood. The biodegradation of arsenobetaine is described, in specific its breakdown by mixed biota with analysis by HPLC-hydride generation-atomic fluorescence spectroscopy (HG-AFS). Subsequent selection within this consortium led us to four bacterial isolates that demonstrated the biodegradation of arsenobetaine to dimethylarsinate. Two of these isolates are identified to species level {Paenibacillus glucanolyticus and Pseudomonas fluorescens A). With analysis by HPLC-inductively coupled plasma-mass spectrometry (ICP-MS), the degradation of arsenobetaine is described by initial cleavage of the methyl arsenic bond to form dimethylarsinoylacetate, with subsequent cleavage of the carboxymethyl-arsenic bond to yield dimethylarsinate. It has been suggested that mixed community function would provide a means for the biodegradation of arsenobetaine, with different communities being capable of breaking the two different types of carbon-arsenic bonds. The present work indicates this is not an obligate requirement and evidence of the monoseptic culture degradation of arsenobetaine has been described. The biogenesis of arsenobetaine, a previously undescribed process, was also investigated. A lysed cell extract of Pseudomonas fluorescens A NCIMB 13944 was shown to transform dimethylarsinoylacetate to arsenobetaine and dimethylarsinate. Dimethylarsinoylacetate is seen as a likely intermediate in the biosynthesis pathway starting at dimethylarsin…
author: Ritchie, Alisdair W.
license: https://dora.dmu.ac.uk/bitstreams/fd54c3f4-10a5-4e46-ab1b-b43217de2266/download
date published: 2006-10
date modified: 2026-07-24T06:18:40Z
provider: De Montfort University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: De Montfort University